The present invention relates to a fuel supply pump, and, more particularly, to a fuel supply pump suitable for use as, for example, an electronic fuel injector for automobile engines.
In, for example, Japanese Laid Open Patent Application No. 55-35197 and Japaneses Utility Model No. 52-5209, a fuel supply pump is fixed in such a manner that a field magnet of an electric motor for driving the pump is secured in a cylindrical yoke by a spring or synthetic resin. However, the fuel supply pump thus structured is generally assembled such that its constitutional components, i.e., a brush, brush spring, brush holder for holding one bearing of an armature, armature, and a pump portion for holding the other bearing of the armature, are axially mounted one by one, thereby resulting in inefficient assembly operation.
A further disadvantage of the above fuel supply pumps resides in the fact that, due to manufacturing tolerances of the individual components such as, for example, the two bearing holding members, the yoke between both holding members, and the brush holder, there are fluctuations in a thrust amount of the armature as well as in a positional relationship between the respective components such as the yoke, magnet and brush.
It is an object of the present invention to provide a fuel supply pump which has the reduced number of components and which is superior in assembling efficiency.
To achieve the above object, in accordance with the present invention, a fuel supply pump is provided which includes an electric motor and a pump driven by the electric motor, with the electric motor and pump being housed in a cup-like casing having at one end thereof an opening and at the other end or the lateral side thereof a pipe for connection with an external hose. The opening is enclosed by an end cover integrally provided with the pipe for connection with said external hose and a terminal, said fuel supply pump includes an electric motor section comprising a holder, including a pair of insulating parts divided about its axis, an armature held at both ends of the holder through bearings, field magnets held on the holder parts; yokes arranged to cover the divided portions of the holder and brush units arranged to be inserted in the respective holder parts. A pump section of the fuel supply pump comprises a rotor mounted to one end of the armature shaft, and a pump-housing fixedly arranged to cover the rotor, the electric motor section and the pump section is covered with the cylindrical casing. The opening of the casing is covered with the end cover, so that both the electric motor section and the pump section are assembled together.
The above and other objects as well as novel features of this invention will be more apparent from the following detailed description with reference to the accompanying drawings.